'Bluffing' Trump made 'empty' threat to N Korea

Former US Defence Secretary and BBC World Affairs Analyst William Cohen says President Donald Trump's "fire and fury" threat against North Korea makes the US look like it was "bluffing".

"The one thing when you're dealing with war is that you have to be very clear, concise and precise and to the extent you create ambiguity, you enhance the danger of miscalculation," he told the BBC’s Laura Trevelyan.